JP2002189159A - Lens holding device and method for correcting eccentricity of lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens holding device capable of correcting the eccentricity of a lens even after the lens is held and fixed. SOLUTION: A frame 11 is provided with an opening 12 so as to house the lenses 2 to 4. An adjusting part 13 has slender shape extended nearly in the tangential direction of the lenses 2 to 4 and is provided with a slender through- hole 13a inside, then both ends in the longitudinal direction of the slender shape are thinned and act as a distortion absorbing part 13b for absorbing distortion caused when the eccentricity of the lenses 2 to 4 is corrected. A guide pin for making the frame 11 slide, in which the lenses 2 to 4 are housed, is inserted in the through-hole 14a of a sleeve part 14 and the through-hole 15a of an ellipse part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens holding device suitable for correcting eccentricity of an optical element constituting an optical apparatus, in particular, a lens used as a photographing lens of a video camera or a digital still camera, and The present invention relates to a lens eccentricity correcting method for correcting eccentricity of a lens held by the lens holding device.

[0002]

2. Description of the Related Art Video cameras and digital still cameras are required to have high image quality, small size, and low price. Since the eccentricity tolerance of a small, high-quality imaging lens is small, if the eccentricity is reduced only by the components (the lens and the holding device for holding the lens), the dimensional tolerance of the holding device and the lens ball itself are reduced. The eccentric tolerance is too small,
The demand for lower prices cannot be satisfied. Therefore,
Various methods have been proposed to prevent the cost of components from increasing by adjusting the eccentricity of the lens without significantly increasing the accuracy of each component.

[0003]

As a method for holding and fixing a lens in a lens holding device, an ultraviolet curing resin or the like is applied to a gap between the lens holding device and the lens, and after the eccentricity adjustment, the lens is cured. When the lens and the lens are bonded, it is difficult to control the adhesive strength between the ultraviolet curable resin and the lens holding device and between the ultraviolet curable resin and the lens, and the fixing reliability is lacking. As another method, when performing so-called crimping by fixing the lens by deforming the lens peripheral portion of the lens holding device to the lens side after adjusting the eccentricity of the lens in the lens holding device, the lens fitting portion of the lens holding device and Since a gap as an eccentricity adjustment margin remains between the lens and the side surface of the lens, when the caulking is incomplete, the lens moves and the eccentricity adjustment may be out of order.

Further, as another method, after adjusting the eccentricity of the lens in the lens holding device, the annular component is screwed into the lens holding device so as to hit the lens, or similarly, the annular component is hit on the lens. Also, when the lens is fitted into the lens holding device, the gap as an eccentricity adjustment margin remains between the lens fitting portion of the lens holding device and the side surface of the lens, so that the eccentricity adjustment may be out of order. .

In either method, the eccentricity of the lens is corrected before the lens is held and fixed by the lens holding device. Therefore, if the eccentricity of the lens is incorrect after the fixing of the lens is completed, the lens is disassembled. Need to be reassembled. Also,
If the lens is fixed or crimped to fix the lens, the lens holding frame will be broken at the time of disassembly, and new components will be required.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and a lens holding device capable of correcting eccentricity of a lens even after holding and fixing the lens, and
It is an object of the present invention to provide a method for correcting eccentricity of a lens that corrects eccentricity of a lens held by the lens holding device.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention provides: (a) a lens holding member formed of a thermoplastic resin for holding one or a plurality of lenses (2-4); In the device (1), a frame (11) having an opening (12) for accommodating the lens, and an elongated shape extending substantially in a tangential direction of the lens and having an elongated through hole (13a) therein, Both ends in the longitudinal direction of the elongated shape are thin, and the both ends are configured to absorb distortion generated when the eccentricity of the lens is corrected.
b) and a first inserted portion (14) having a hole (14a) into which a first guide pin (22) for sliding the frame containing the lens is inserted. ) And a second inserted portion (15) having a hole or groove (15a) into which a second guide pin (23) for sliding the frame containing the lens is inserted.
(B) a method for correcting eccentricity of the lens held by the lens holding device of (a), wherein the method comprises: A first step of restraining the posture or shape of the lens holding device in a state where the eccentricity of the lens housed in the frame is corrected, and eliminating a stress generated in the strain absorbing section by the first step. And a second step of heating the strain absorbing portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a lens holding device and a method for correcting eccentricity of a lens according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing one embodiment of the lens holding device of the present invention, FIG. 2 is a plan view showing one embodiment of the lens holding device of the present invention, and FIG. 3 is a zoom lens using the lens holding device of the present invention. FIG. 4 is a cross-sectional view showing an overall configuration example of an eccentricity correcting device for correcting eccentricity of a lens held by the lens holding device of the present invention, and FIG. FIG. 3 is a partial plan view showing an eccentricity correcting device for correcting eccentricity of a held lens.

In FIG. 1, a lens holding device 1 of the present invention is shown.
Stores and holds three lenses 2 to 4 as an example. The number of lenses is not limited to three, but may be one or more. The lenses 3 and 4 are combined and integrated. The specific configuration of the lens holding device 1 is shown in FIGS.
This will be described with reference to FIG. FIG. 2 shows a state where the lenses 2 to 4 are housed in the lens holding device 1.

1 and 2, a lens holding device 1 is shown.
Has a frame 11 in which a circular opening 12 for accommodating the lenses 2 to 4 is formed. At one end of the frame 11, a cylindrical sleeve portion 14 is formed via an adjusting portion 13. The other end of the frame 11 has an oval through hole 15a.
Is formed. Sleeve part 14
The through hole 14a is for inserting a guide pin 22 described later, and the hole 15a of the elongated hole portion 15 is for inserting a guide pin 23 described later. As shown in FIG. 2, the hatched outer end of the elongated hole 15 may be deleted to form an elongated groove.

The adjusting unit 13 is a lens holding device 1 according to the present invention.
And the configuration thereof will be described in detail. The adjusting portion 13 has an elongated shape extending substantially in the tangential direction of the lenses 2 to 4, in other words, extending in a direction substantially orthogonal to the axis A indicated by a dashed line connecting the center axis of the sleeve portion 14 and the center of the opening 12. It has an elongated shape, and an elongated through hole 13a is formed at the center thereof. When the lens holding device 1 holding the lenses 2 to 4 is used as a part of the zoom lens, the adjusting unit 13 has an elongated shape extending in a direction intersecting the moving direction of the lens holding device 1.

In the present embodiment, the adjusting portion 13 is not formed in a straight line, and the end of the upper portion and the end of the lower portion of FIG. It is inclined. Therefore, the adjusting portion 13 has a shape that is slightly bent about the axis A.
The thickness of the periphery of the hole 13a is substantially uniform, but both ends in the longitudinal direction of the adjusting portion 13 are thin. The thin portions serve as the strain absorbing portions 13b and 3b.

The above-described lens holding device 1 is integrally formed of, for example, a thermoplastic resin such as polycarbonate. The distortion absorbing portions 13b and 3b function to absorb distortion of the entire lens holding device 1 when correcting eccentricity of the lenses 2 to 4 described later.

A configuration in which a zoom lens such as a video camera or a digital still camera is configured using the lens holding device 1 shown in FIGS. 1 and 2 will be described. FIG. 3 shows a state in which the entire zoom lens is disassembled. Here, a case where the zoom lens is configured using two lens holding devices 1 shown in FIGS. 1 and 2 is shown. In FIG. 3, the lens holding device 1 shown in FIGS. 1 and 2 is used as one component of the zoom lens, and therefore the lens holding device 1 is slightly modified. ,
It is not different from that shown in FIG.

In FIG. 3, two lens holding devices 1 holding lenses 2 to 4 respectively have two guide pins 2.
2 and 23 and stored in the lens barrel 21. The lenses 2 to 4 held by the lens holding device 1 are fixed to the lens holding device 1 after the eccentricity is corrected by an eccentricity correction method described later, and are stored in the lens barrel 21.

The guide pin 22 is inserted into the hole 14a of the sleeve portion 14 of the lens holding device 1, and the guide pin 23
Is inserted into the hole 15a of the long hole portion 15. The diameter of the hole 14a is set such that the guide pin 22 does not rattle as much as possible and the lens holding device 1 can move smoothly. The guide pin 23 can slide only in the longitudinal direction of the hole 15a.

When the lens holding device 1 is stored in the lens barrel 21, the lid 24 is covered. A drive unit 25 having motors 25a and 25b for sliding the lens holding device 1 is attached to the lid 24. A nut is attached to the back surface of the drive unit 25, and the nut is attached to the motor 25a,
It moves in the longitudinal direction by the rotation of 25b.

The lens holding device 1 has an engaging portion 1 not shown in FIGS.
6 is attached. When a zoom operation is performed by a video camera, a digital still camera, or the like, the motor 25
a, 25b rotate and the lens holding device 1
Slide along 2 and 23. A groove 24a is formed in the lid 24, and an aperture 26 is inserted into the groove 24a. The diaphragm 26 is arranged between the two lens holding devices 1. The zoom lens is configured as described above.

Next, a method for correcting eccentricity of the lenses 2 to 4 housed in the lens holding device 1 will be described. The eccentricity of the lenses 2 to 4 housed in the lens holding device 1 is corrected by the eccentricity correcting device shown in FIGS. In FIG. 4, the lenses 2 to 4 are housed in the opening 12 of the frame 11 and fixed by caulking as in the related art, as described in FIGS. In addition, the diameter of the opening 12 is the lens 2-4.
Is set to light press fit. If the material of the lens holding device 1 is made of plastic which is inexpensive and easy for injection molding,
It is easy to make the lenses 2 to 4 lightly press-fit.

Lens holding device 1 holding lenses 2 to 4
Is a fixed bell clamp 32 provided on the frame 31.
And the movable bell clamp 33. The frame 31 has a substantially U shape when viewed from the left and right directions in FIG. In the lower part of the frame 31,
Guide pins 34 and 35 are provided, and the sleeve 1
The guide pin 34 is inserted into the hole 14a of the
The guide pin 35 is inserted into the hole 15a. The bell clamp 32 receives the lower surface of the lens 4 and receives the guide pins 34 and 3.
5 regulates the position of the lens holding device 1.

When the lenses 2 to 4 are sandwiched between the bell clamps 32 and 33, the lenses slide in a direction in which the axes of the bell clamps 32 and 33 coincide with the axis connecting the spherical centers of the upper and lower surfaces of the lenses. Thereby, the eccentricity of the lenses 2 to 4 is corrected. At this time, distortion occurs in the lens holding device 1. This distortion is caused by a manufacturing error of the lens holding device 1, the lenses 2 to 4
Is caused by absorbing the centering error of the lens and the assembly error of the lenses 2 to 4. More specifically, the lens holding device 1
Has an adjusting portion 13, and both ends in the longitudinal direction of the adjusting portion 13 are thin-walled strain absorbing portions 13b and 3b. Therefore, the above-mentioned strain is mainly absorbed by the deformation of the absorbing portions 13b and 3b. I have.

The eccentricity correcting device shown in FIG. 4 includes heating units 36 and 36 as shown in FIG.
The adjusting unit 13 is heated by the heating units 36, 36. As shown in FIG. 5, the heating units 36, 36
3 contact the strain absorbing portions 13b, 3b, and
b, 3b are heated. At this time, the strain absorbing portions 13b, 3
The temperatures and heating times of the heating units 36, 36 are set so that the temperature b becomes an appropriate temperature between the glass transition point and the melting point of the lens holding device 1 (strain absorbing unit 13b) and below the melting point. Heating unit 3
If the heater 6 is heated by an electric current, the amount of the electric current may be appropriately set. When the material of the lens holding device 1 is polycarbonate, the appropriate temperature is approximately 160 ° C to 180 ° C.

Then, the distortion absorbing sections 13b, 13b,
The stress applied to 3b is eliminated. Heating unit 36,3
6, the bell clamp 33 is moved upward in a state where the temperatures of the strain absorbing portions 13b and 3b are lower than the glass transition point, and the lens holding device 1 is taken out.
Thus, the correction of the eccentricity of the lenses 2 to 4 is completed.

In this embodiment, the bell clamps 32 and 33 are used as means for correcting the eccentricity of the lenses 2 to 4 and forcibly restraining the posture and shape of the lens holding device 1. However, the present invention is not limited to this. It is not something to be done. Light is applied to the lenses 2 to 4, the positions and postures of the lenses 2 to 4 are detected by the reflected light from the lenses 2 to 4, the positions and postures of the lenses 2 to 4 are corrected, and some mechanical restraint is performed. Is also good. Further, an image of a chart (test subject) may be formed by the lenses 2 to 4, the symmetry of the formed image with respect to the optical axis may be detected, the position and orientation may be corrected, and some mechanical constraint may be performed. .

The heating unit 36 is not limited to a heating wire, but may be any device, such as a laser or high-frequency dielectric heating, as long as it can heat the strain absorbing units 13b and 3b of the adjusting unit 13. . The eccentricity correction by the eccentricity correction method described above can be repeatedly performed until a predetermined accuracy is obtained.

[0026]

As described in detail above, the lens holding device of the present invention has a frame having an opening for accommodating a lens,
When the lens has an elongated shape extending substantially in the tangential direction, has an elongated through hole therein, and both ends in the longitudinal direction of the elongated shape are made thin, and both ends correct the eccentricity of the lens. An adjusting portion that acts as a strain absorbing portion that absorbs a distortion generated in the lens, a first inserted portion having a hole into which a first guide pin for sliding a frame that houses the lens is inserted, and a lens that houses the lens A second insertion portion having a hole or a groove into which a second guide pin for sliding the frame is inserted, and the method of correcting eccentricity of a lens according to the present invention is provided in the frame. With the eccentricity of the lens corrected, the posture or shape of the lens holding device is restrained, and the strain absorbing portion is heated so as to eliminate the stress generated in the strain absorbing portion. Even after fixing the lens, It is possible to modify the.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a lens holding device of the present invention.

FIG. 2 is a plan view showing an embodiment of the lens holding device of the present invention.

FIG. 3 is an exploded perspective view showing a zoom lens using the lens holding device of the present invention.

FIG. 4 is a cross-sectional view showing an overall configuration example of an eccentricity correcting device for correcting eccentricity of a lens held by a lens holding device of the present invention.

FIG. 5 is a partial plan view showing an eccentricity correcting device for correcting eccentricity of a lens held by the lens holding device of the present invention.

[Explanation of symbols]

 Reference Signs List 1 lens holding device 2-4 lens 11 frame 12 opening 13 adjusting portion 13b strain absorbing portion 14 sleeve portion (inserted portion) 14a through hole 15 elongated hole portion (inserted portion) 15a through hole 22, 23 guide pin 33, 34 Bell clamp 36 heating unit

Claims (2)

[Claims] 1. A lens holding device formed of a thermoplastic resin holding one or a plurality of lenses, comprising: a frame having an opening for housing the lens; and an elongated shape extending substantially in a tangential direction of the lens. It has an elongated through-hole inside, and both ends in the longitudinal direction of the elongated shape are made thin, and the both ends act as strain absorbing portions for absorbing distortion generated when eccentricity of the lens is corrected. An adjusting section; a first inserted section having a hole into which a first guide pin for sliding the frame containing the lens is inserted; and a second section for sliding the frame containing the lens. A second insertion portion having a hole or a groove into which the guide pin is inserted. 2. A method of correcting eccentricity of a lens held by a lens holding device according to claim 1, wherein said eccentricity of said lens housed in said frame is corrected. A first step of constraining the posture or shape of the lens holding device; and a second step of heating the strain absorbing section so as to eliminate the stress generated in the strain absorbing section by the first step. A method for correcting eccentricity of a lens, characterized in that: